title: Phenolic constituents from the roots of Mikania micrantha and their allelopathic effects.
abstract: Four new thymol derivatives, 8,10-dihydroxy-9-benzoyloxythymol (1), 9-isobutyryloxy-10-hydroxythymol (2), 7,8,9,10-tetrahydroxythymol (3), and 7,8,10-trihydroxy-9-E-feruloyloxythymol (4), were isolated from the fresh roots of Mikania micrantha , along with 8,9,10-trihydroxythymol (5), 8,10-dihydroxy-9-acetoxythymol (6), 8,10-dihydroxy-9-isobutyryloxythymol (7), 8,10-dihydroxy-9-(2-methylbutyryloxy)thymol (8), 8,9-dehydro-10-hydroxythymol (9), 8-methoxy-9-hydroxythymol (10), ethyl caffeate (11), ethyl ferulate (12), 3,5-di-O-caffeoylquinic acid (13), and mikanin (14). Their structures were determined by spectroscopic methods. The known thymol derivatives (5-10) were obtained from the genus Mikania for the first time. Allelopathic effects of these compounds on Arabidopsis thaliana seeds were evaluated by a filter paper assay. After the treatment at 0.1 mM for 4 days, the seed germination rate with compound 8 was 48% and the inhibitory rates of shoot growth with compounds 1, 2, 7-10, and 12 were over 40%. The IC50 values of compounds 1 and 8 on shoot growth were 342.5 and 625 μM, respectively.
authors.affiliation: Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Tianhe District, Guangzhou, People's Republic of China.
authors.forename: Qiaolin
authors.initials: Q
authors.lastname: Xu
authors.forename: Haihui
authors.initials: H
authors.lastname: Xie
authors.forename: Huilin
authors.initials: H
authors.lastname: Xiao
authors.forename: Xiaoyi
authors.initials: X
authors.lastname: Wei
mesh_terms: D064089:Allelopathy / Q000187:drug effects*; D017360:Arabidopsis / Q000187:drug effects / Q000254:growth & development; D018525:Germination / Q000187:drug effects; D035742:Mikania / Q000737:chemistry*; D015394:Molecular Structure; D010636:Phenols / Q000737:chemistry / Q000494:pharmacology*; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D018517:Plant Roots / Q000737:chemistry; D012639:Seeds / Q000187:drug effects / Q000254:growth & development
chemical_list: D010636:Phenols; D010936:Plant Extracts